• 한국실내디자인학회논문집
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• 제16권2호
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• pp.163-171
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• 2007

The present study approached the characteristics of various space compositions in contemporary residential architecture through the concept of ex-formality, and found that ex-formal spaces are composed through the variation of floor, wall, ceiling or roof and derived four types of ex-formal space composition - ex-cubic space composition using folding, plastic space composition using the plasticity of concrete, atypical space composition using geometric manipulation, and non linear space composition using digital technology. Based on this, additionally, we derived elements expressing the characteristics of ex-formal space composition, which are obliqueness, inclination, flexibility in ex-cubic space composition using folding, plasticity and fluidity in plastic space composition using the plasticity of concrete, ex-construction, dynamism and asymmetry in atypical space composition using geometric manipulation, and flexibility, fluidity, self similarity and plasticity in non linear space composition using digital technology. On the other hand, this study purposed to help understand various space expression patterns of contemporary residential architecture by analyzing how these types of ex-formal space composition and polysemous expression characteristics have been represented in contemporary residential architecture since the 1990s.

• 한국전산유체공학회지
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• 제15권4호
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• pp.25-31
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• 2010

Interface tracking of two phase is significant to analyze multi-phase phenomena. The VOF(Volume of Fluid) and level set are well known interface tracking method. However, they have limitations to solve compressible flow and incompressible flow at the same time. CIP(Cubic Interpolate Propagation) method is appropriate for considering compressible and incompressible flow at once by solving the governing equation which is divided up into advection and non-advection term. In this article, we analyze the droplet impingement according to various We number using improved CIP method which treats nonlinear term once more comparison with original CIP method. Furthermore, we compare spread radius after droplet impingement on the wall with the experimental data and original CIP method. The result using improved CIP method shows the better result of the experiments, comparison with result of original CIP method, and it reduces the mass conservation error which is generated in the numerical analysis comparison with original CIP method.

• 한국정밀공학회지
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• 제20권2호
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• pp.184-191
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• 2003

A parallel manipulator has high stiffness and all the joint errors on the device are not accumulated at the end -effector unlike a serial manipulator. These are the reasons why the parallel manipulator has been widely used in many fields of industry. In the parallel manipulator, it is very important to predict the exact pose of the end-effector when we want to control the end-effector motion. Installation errors have to be determined in order to predict and control the actual position and pose of the end-effector. This paper presents an algorithm to find the whole 36 joint error components with joint clearance errors and measurement errors considered, when a link length measurement sensor is used and data more than 36 times are acquired for 36 different configurations. A simulation test using this algorithm is performed with a Matlab program which uses the Levenberg-Marquardt method that is known to be efficient for non-linear optimization.

• 한국산림과학회지
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• 제102권4호
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• pp.499-505
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• 2013

소나무재선충병(Bursaphelenchus xylophilus)은 한국, 일본, 그리고 중국과 같은 동아시아의 소나무류 산림에 심각한 피해를 유발시킨다. 재선충병에 의한 병해는 그 치료방법이 훈증, 소각외에는 거의 없기 때문에 감염목을 조기 탐지하여 그 피해가 주변 임목 및 임분에 확산되지 않도록 하는 것이 최선책이라 할 수 있다. 본 연구에서는 소나무재선충병 감염목과 비감염목의 분광반사율을 주기적으로 측정하여 감염목의 분광반사 특성을 구명하였다. 이를 위하여, 6월에서 10월까지 GER3700 spectroradiometer를 이용하여 감염목과 비감염목의 400 nm~2,500 nm 파장대의 분광반사값을 측정하였다. 측정된 값의 noise를 보정하기 위하여 cubic spline 보간법을 사용하였다. 그 결과, 대부분의 감염목들은 재선충 주입 후 2개월 이내에 적색(600 nm~700 nm) 그리고 중적외선(1,400 nm~1,500 nm) 파장대에서 분광반사값의 변화를 보였으나, 비감염목들의 분광반사값은 어느 파장대에서도 특별한 변화가 나타나지 않았다. 시기별로 감염목과 비감염목의 분광반사값 변화를 통계적으로 비교해 본 결과, 소나무재선충 주입 2달 후 적색 파장대역과 중적외선 파장대역에서 가장 빠르게 통계적으로 유의한 차이를 보였으나(p<0.05), 근적외선 파장대역에서는 통계적으로 유의한 차이가 나타나지 않았다(p>0.05). 따라서 적색과 중적외선 파장대역에서의 분광반사율 변화를 통해 소나무재선충병 감염목의 조기 탐지가 가능한 것으로 판단되었다.

• 디지털산업정보학회논문지
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• 제16권3호
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• pp.49-58
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• 2020

Image interpolation, a technology that converts low resolution images into high resolution images, has been widely used in various image processing fields such as CCTV, web-cam, and medical imaging. This technique is based on the fact that the statistical distributions of the white Gaussian noise and the difference between the interpolated image and the original image is similar to each other. The proposed algorithm is composed of three steps. In first, the interpolated image is derived by random image interpolation. In second, we derive weighting functions that are used to apply non-local mean filtering. In the final step, the prediction error is corrected by performing non-local mean filtering by applying the selected weighting function. It can be considered as a post-processing algorithm to further reduce the prediction error after applying an arbitrary image interpolation algorithm. Simulation results show that the proposed method yields reasonable performance.

• Steel and Composite Structures
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• 제32권4호
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• pp.509-519
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• 2019

In this paper, an analytical approach for the free vibration analysis of spiral stiffened functionally graded (SSFG) cylindrical shells is investigated. The SSFG shell is resting on linear and non-linear elastic foundation with damping force. The elastic foundation for the linear model is according to Winkler and Pasternak parameters and for the non-linear model, one cubic term is added. The material constitutive of the stiffeners is continuously changed through the thickness. Using the Galerkin method based on the von $K\acute{a}rm\acute{a}n$ equations and the smeared stiffeners technique, the non-linear vibration problem has been solved. The effects of different geometrical and material parameters on the free vibration response of SSFG cylindrical shells are adopted. The results show that the angles of stiffeners and elastic foundation parameters strongly effect on the natural frequencies of the SSFG cylindrical shell.

• 대한기계학회논문집
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• 제19권8호
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• pp.1901-1906
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• 1995

The frequency response functions of systems incorporating a non-linear cubic stiffness subject to sinusoidal excitation are derived using the Volterra series and the convergence characteristics investigated. It is shown that the series representation of the frequency response functions converges only when the sinewave input amplitude is within a certain range. Within the range of convergence the frequency response function based on the Volterra series approaches the analytical one as more higher order frequency response function terms are included. Proposed is a criterion for the studies systems to predict approximately the range of sinewave input amplitude for which the series representation of the frequency response functions converges.

• Steel and Composite Structures
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• 제20권5호
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• pp.1087-1102
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• 2016

The paper proposes to characterize the free vibration behaviour of non-uniform cylindrical shells using spline approximation under first order shear deformation theory. The system of coupled differential equations in terms of displacement and rotational functions are obtained. These functions are approximated by cubic splines. A generalized eigenvalue problem is obtained and solved numerically for an eigenfrequency parameter and an associated eigenvector which are spline coefficients. Four and two layered cylindrical shells consisting of two different lamination materials and plies comprising of same as well as different materials under two different boundary conditions are analyzed. The effect of length parameter, circumferential node number, material properties, ply orientation, number of lay ups, and coefficients of thickness variations on the frequency parameter is investigated.

• 소성∙가공
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• 제12권6호
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• pp.572-581
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• 2003

In this paper, an automatic surface construction method based on B-spline surface and scalar field theory is proposed to generate the extrusion die surface of non-symmetric H-and U-shaped sections. The isothermal lines and stream lines designed in the scalar field are introduced to find the control points which are used in constructing B-spline surfaces. Intersected points between the isothermal lines and stream lines are used to construct B-spline surfaces. The inlet and outlet profiles are precisely described with B-spline curves by using the centripetal method for uniform parameterization. The extrusion die surface is generated by using the cubic curve interpolation in the u-and v-directions. A quantitative measure for the control of surface is suggested by introducing the tangential vectors at the inlet and outlet sections. To verify the validity of the proposed method, automatic surface generation is carried out for extrusion die of non-symmetric H-and U-shaped sections.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.494-494
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• 2013

Atmospheric pressure non-thermal plasma of the needle-typed interaction with aqueous solutions has received increasing attention for their biomedical applications [1]. In this context, surface discharges at bio-solutions were investigated experimentally. We have generated the non-thermal plasma jet bombarding the bio-solution surface by using an Ar gas flow and investigated the emission lines by OES (optical emission spectroscopy) [2]. Moreover, The non-thermal plasma interaction with bio-solutions has received increasing attention for their biomedical applications. So we researched, the OH radical density of various biological solutions in the surface by non-thermal plasma were investigated by Ar gases. The OH radical density of DI water; deionized water, DMEM Dulbecco's modified eagle medium, and PBS; 1x phosphate buffered saline by non-thermal plasma jet. It is noted that the OH radical density of DI water and DMEM are measured to be about $4.33{\times}1016cm-3$ and $2.18{\times}1016cm-3$, respectively, under Ar gas flow 250 sccm (standard cubic centimeter per minute) in this experiment. The OH radical density of buffer solution such as PBS has also been investigated and measured to be value of about $2.18{\times}1016cm-3$ by the ultraviolet optical absorption spectroscopy.